Value of Rod Pump Control

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					    Value of
Rod Pump Control

               TWP-003 Rev. O
Value of Rod Pump Control                                             eProduction Solutions, Inc.

          Value of Rod Pump Control
                   Louis Ray – Product Line Manager / Trainer / Consultant

   Many excellent articles and technical papers over the years have documented the economic
   and operating benefits achieved by installing pump off control on rod pumped wells. This
   paper not only examines the most common problem associated with rod pumping –
   displacement control, but it defines “pump off”, as well as reviews and summarizes the
   benefits of rod pump control already documented in past articles and technical papers. In
   addition, this paper provides numerous examples of case studies with microprocessor-based
   rod pump controllers (RPCs).

   The estimates of benefits cited in this paper are based on field experience, customer dialog,
   and expert input. These benefits and typical improvements are based on specific case
   studies and should be used only as a guide to estimate the potential benefits of rod pump
   control in a particular situation.

   A common operating problem in a sucker rod pumping system is trying to match inflow into
   a well with an installed beam pumping system that has a fixed displacement. Because the
   amount of fluid entering a well is constantly changing as the well pumps down or is re-
   charged by the well’s inflow, the displacement of the installed beam pumping system almost
   never exactly matches the ability of the well to produce fluid. Therefore, the well is usually
   either “under-produced” (which means that the maximum production capacity of the well is
   not being produced) or “over-produced” (which means that the pumping system
   displacement is greater than the amount of fluid moving into the wellbore).

   Both of these conditions are less than acceptable. Under-producing results in loss of revenue
   because oil that could be sold is not being produced. Over-producing also has quite serious
   consequences. For example, when the pumping system has a capacity of one gallon per
   stroke, but only one-half gallon flows into the well bore, fluid pound occurs when the
   downward moving plunger strikes the fluid in the partially filled rod pump barrel. The pump
   plunger instantaneously stops until the load is transferred from the rods to the tubing,
   causing the rods to “stack out” or go into compression. This shock loading causes damage to
   the sucker rods, the bottom hole pump, as well as the pumping unit. Also, if the pumping
   system displacement is one gallon per stroke, but has only one half gallon per stroke
   available to pump, the energy required to operate the pumping system is almost the same
   as if the system was producing one gallon per stroke.

   Many methods have been used to try to match the displacement of rod pumped systems and
   the ability of a well to produce fluid. When using a gas engine as a pumping unit prime
   mover, this is possible by simply regulating the gas engine speed. Systems (Variable Speed
   Drives) that change electric motor speed (based on the degree of inflow detected) to
   regulate SPM to match the well inflow performance are currently more expensive than other
   available methods. This solution is, however, applicable under certain conditions: heavy
   crude / high sand content wells or wells that must be controlled because of other extreme
   downhole conditions or that cannot be shut down for long periods of time.

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Value of Rod Pump Control                                               eProduction Solutions, Inc.

   A common method to match capacities is to size the pumping system to have surplus
   capacity and then shut the unit down for some period of time (idle time) to allow fluid to
   build up in the wellbore. At start-up, the system pumps the fluid that accumulated in the
   wellbore during the idle time plus the fluid that comes in while the pumping unit is running.
   The pumping unit is then shut down for another period of idle time.

   Two of the most widespread devices used for this type of “intermittent pumping” are the “pin
   type” timer and the “percent” timer. Both devices are inexpensive and easy to understand.
   However, the minimum cycle (run time or idle time) time available in most pin type timers is
   fifteen minutes. Unless the run time setting is constantly changed to meet the changing fluid
   inflow, the same situation exists – “over-pumping” or “under-pumping”. The fifteen-minute
   restriction for total run time or total idle time almost always results in over-pumping or
   under-pumping. A variation on the time clock is the percent timer. A percent timer operates
   on properly setting a percentage of each fifteen-minute period as pumping unit run time.
   The remainder of the fifteen-minute period is assigned as the well’s idle time. Both devices
   require frequent attention from the operator if they are to work in the operator’s favor at all.
   To find a reasonable setting, the operator must try a selected runtime setting, then check
   this setting against daily production or sonic fluid level and then re-adjust the setting as
   needed. This process is never ending!

   The best solution to this “displacement versus inflow” problem is to use a RPC that
   automatically detects when the pumping system is beginning to run out of available fluid to
   pump and then shuts the well down for an adjustable “idle time” to allow the well inflow to
   replenish fluid in the wellbore. Ideally, this idle period should be based on specific well inflow
   conditions so that the production lost due to backpressure caused by the building fluid level is
   minimized. The rod pumped system starts pumping again after this idle period and pumps
   until the well starts to “pound fluid” again.

   There have been many attempts to develop a basis for “rod pump control” that will do a
   precise job of pumping each well with maximum efficiency. Methods that have been used to
   detect when the well should be shut down include: a simple “flow/no flow” paddle in the
   flowline, shock or impact sensing devices on the polished rod or bridle carrier, motor
   horsepower, motor speed, etc. The most successful RPCs measure the polished rod load and
   position for a qualitative or quantitative dynamometer card (refer to the next section –
   “Understanding A Rod Pumped Well”). This gives positive real-time knowledge of what is
   happening in a rod pumped well. The introduction of the low cost PC computer has made it
   possible to combine this information with the logic necessary to diagnose and control the well
   completely in any situation. Bottomhole and surface equipment analysis software packages
   that use this load and position information make rod pump control a complete pump off
   control and analysis system. The addition of radio or hard wire transmission of this
   information to a central location for analysis and action further expands the utility of the
   system. It makes it possible to know the specific performance of every well at all times and
   to take any necessary corrective action at the earliest possible time.

   The success of any pump off control method, even the sophisticated ones described above, is
   dependent on several factors. The most important factor is the control logic set up for each
   well. The selection of pump off shutdown criteria and idle times to maximize production
   depends on:

      1. The reservoir pressure.
      2. The inflow characteristics of each well.
      3. The size of the casing and tubing.
      4. The displacement of the installed rod pumping system.

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Value of Rod Pump Control                                               eProduction Solutions, Inc.

Understanding a Rod Pumped Well
   Surface Analysis

   Through the years, the polished rod dynamometer has been the principal tool for analyzing
   the operation of rod pumped wells. A dynamometer system gathers polished rod load and
   displacement “points” and plots the resulting “curve” - which is commonly known as the
   “surface dynamometer card”. The shape of this card is affected by changing downhole
   conditions. Ideally, these conditions would be apparent from the surface card by visual
   interpretation. However, because of the complex behavior of the rod string and the great
   diversity of card shapes, visual diagnosis is not always possible. Though much information
   can be gained from visual interpretation of surface cards, success is directly linked to the skill
   and experience of the analyst – and even the most experienced analysts can be misled into
   an incorrect diagnosis.

   Bottom Hole Analysis

   In the studies of surface dynamometer cards, it is understood that one of the primary things
   that affect the shape of the actual dynamometer card is the load condition at the bottom of
   the hole. Theoretical surface dynamometer cards are all based on ideal pumping conditions
   with full pump fillage. In "real" rod pumped wells, the pump fillage is never completely full.
   In addition, bottom hole conditions such as crooked hole, paraffin, scale, sand, and solids all
   affect the loads and the shape of the surface dynamometer card.

   In an effort to find out exactly what was happening at the bottom of the hole, W. E. Gilbert
   and others designed a bottom hole dynagraph that measured loads and displacements at the
   bottom of the hole. His work was published in 1936. In 1967, Sam Gibbs received a patent
   on a mathematical method for simulating the sucker rod pumping system – commonly
   known today as the “wave equation” solution. His work and the work of others made it
   possible to use a surface dynamometer card as a basis for a simulated bottom hole card. In
   1986, G. Albert designed an electronic bottom hole analyzer, which measured the bottom
   hole conditions electronically in the same manner that W. E. Gilbert had measured them
   mechanically.      This tool confirmed that the mathematical simulation from surface
   dynamometer cards does indeed give accurate bottom hole loads and displacements.

   The mysterious "black magic" of the experienced dynamometer analyst was the result of a
   lifetime of observation and experience. Today, with a thorough understanding of the
   principles and aided by computer simulation, an accurate analysis of a well problem is
   possible in nearly every case. The calculated subsurface or downhole card removes personal
   judgment and experience from the diagnosis of downhole pumping conditions.

   Predictive Programs

   Wave equation based computer predictive programs greatly facilitate the setting up of load
   limits, pump off set points, idle times, and all other control parameters of a RPC. Well
   conditions can be simulated under a variety of normal and abnormal operating conditions.
   The operator can build a library of expected dynamometer cards covering most operational
   conditions. He then can make a much more practical analysis of problems when they occur.
   Unfortunately, not all wells can economically justify a “top of the line” RPC. eProduction
   Solutions offers a low cost solution for these low-producing wells – discussed later in this
   paper. In addition, some bottom hole conditions or wellbore configurations make control with
   an RPC impossible.

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Value of Rod Pump Control                                               eProduction Solutions, Inc.

Explanation of “Fluid Pound” or “Pump Off”
   Pounding fluid can shorten the life of the rod string, as well as that of the pumping unit.
   When pounding fluid, the rods and the fluid in the top portion of the downstroke act as a
   “free falling body” at the position of the plunger. If the point of “fluid pound” is in the upper
   portion of the pump stroke, the plunger could hit with an impact greater than the combined
   rod and fluid weight. Matching pump displacement to well inflow or the use of RPCs can help
   to prevent fluid pound.

                                                               Fluid Pound, as experienced in a
                                                               pumping oil well, is caused by the
                                                               pump not completely filling with
                                                               fluid on the upstroke.       As the
                                                               downstroke begins, the entire fluid
                                                               and rod string load moves down
                                                               through a “void” until the plunger
                                                               “hits” the fluid level in the pump
                                                               barrel. The traveling valve opens,
                                                               suddenly transferring the load
                                                               from the rod string to the tubing,
                                                               causing a sharp decrease in load
                                                               that, in turn, transmits a shock
                                                               wave throughout the pumping
                                                               system.        This shock wave
                                                               damages the components of the
                                                               pumping system.

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Value of Rod Pump Control   eProduction Solutions, Inc.

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Value of Rod Pump Control                                          eProduction Solutions, Inc.

   Uncontrolled Fluid Pound
      •   Increases energy costs.
      •   Increases wear and tear on downhole equipment.
      •   Makes it almost impossible to counterbalance the pumping unit properly.
      •   The counterbalance problem and the fluid pound "shock" increase gearbox wear and
          shorten gearbox and wrist pin bearing life.

   Fluid Pound Control Using a Rod Pump Controller
      •   Accelerates oil recovery

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Value of Rod Pump Control                                               eProduction Solutions, Inc.

          •   By detecting high fluid levels that cause backpressure on the producing formation
              and therefore reduce fluid inflow into the wellbore.
          •   By the detection of worn out pumps before production loss is noticed.
          •   By early detection of any problem that might cause the well to stop pumping -
              necessary repairs can be started immediately.
          •   By alarming immediately when one of the above conditions occur.

      •   Saves energy

          •   “Rule of thumb” – An RPC saves $600 per polished rod horsepower per year.
              (This savings was verified through studies conducted by Robert Gault, a respected
              artificial lift engineer and teacher.)
          •   Requires a reduction of only five or six polished rod horsepower for a one year
              payout of the rod pump control equipment.

      •   Extends the life of the downhole pump and rod string

          •   Ten strokes per minute amounts to 5,250,000 strokes per year. The average life
              of a rod string is about 20,000,000 strokes. The average life of a downhole pump
              is about 5,000,000 strokes. If a well’s runtime is reduced by 25%, the rod string
              will last one year longer and the pump will last three months longer.

      •   Eliminates downhole problems

          •   Eliminates rod failures at the pump by stopping rod "buckling" low in the rod
              string when the plunger is “stopped” by fluid pound.
          •   Eliminates low tubing splits because fluid pound control stops tubing wear from
              rod buckling.
          •   The elimination of about one to three low rod or tubing failures will justify the cost
              of installation of a RPC.

Percentage Timers Vs. Rod Pump Control
   A percentage timer is a timing device used to control the operation of a pumping well. The
   timer can be set to turn the pumping unit “on” for part of a 15 minute interval and then turn
   it “off” for the remaining portion of the 15 minutes. For example, a timer can be set to run a
   pumping unit for five minutes and turn it off for ten minutes (to pump 33% of the time).
   Timers are simple, easy to use, and inexpensive. However, percentage timers are effective
   only if the operator can keep them adjusted correctly based on changing well conditions. If a
   well remains stable for a long time, a percentage timer may be sufficient to minimize fluid
   pound. However, a well with fluctuating production will be very difficult to control with a
   percentage timer. In this situation, a RPC is the only practical solution to minimize fluid
   pound damage, while maintaining maximum production.

   A RPC turns the unit off only if it detects fluid pound or if an operator-selected load violation
   occurs. Therefore, it automatically adjusts the pumping rate to changing well conditions.
   RPCs can be thought of as "smart" percentage timers. On the contrary, percentage timers
   are "dumb" devices because they turn the motor on or off at the pre-set times regardless of
   well conditions. For example, if the well's inflow rate increases due to a waterflood response,
   a percentage timer will continue to pump the well at the same rate as before. This causes
   the fluid level to rise and may reduce production. For declining production, a percentage

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Value of Rod Pump Control                                             eProduction Solutions, Inc.

   timer that is not frequently adjusted will not prevent fluid pound.       Therefore, system
   efficiency and equipment life will decrease.

“Stand-alone” Rod Pump Control Systems
   Modern RPCs can operate either as a stand-alone device or as part of a centralized
   automation system. This is possible because modern controllers contain all logic needed to
   operate each rod pumped well independently. However, when RPCs are used as stand-alone
   devices, they must be visually inspected for alarm and electronic malfunctions on a regular
   basis, usually daily. It is also a good idea check to the calibration of the load and position
   transducers periodically with a calibrated stand-alone dynamometer system. Although
   stand-alone rod pump control systems cost less than supervisory centralized systems, they
   must be manually checked to ensure they are functioning properly.                Control logic
   parameters, and start-up and shutdown dynamometer cards can be reviewed or changed on
   site with a portable analyzer, usually a laptop computer. This portable analyzer plugs into a
   port on the outside of the RPC enclosure.

“Supervisory” Rod Pumped Control Systems
   Supervisory rod pump control systems (CAO or “Computer Assisted Operations”) represent
   the state-of-the-art in rod pump control application. These systems consist of a central
   computer that communicates with a number of wells with installed RPCs via radio, direct
   cable, cellular telephone or satellite telemetry. The operator of the central computer system
   can monitor any single well or scan several wells using a specially designed software
   package. The system can produce individual well performance reports that show the
   average runtime, present status of the well (“on”, “off”, “down”), alarms for load or run-time
   violations, etc. Dynamometer cards can be transferred from the individual controllers to the
   central computer for further analysis. A complete surface and downhole equipment analysis
   can be done by the host software to detect problems. In addition, RPC control parameters
   can be viewed or changed via the central system. Centralized systems have higher capital
   costs than stand-alone systems and may require significant changes in field personnel job
   functions. However, since central systems can detect well problems faster and more
   accurately than stand-alone systems, they actually help optimize manpower usage (operate
   by exception). Instead of manually inspecting each well, field personnel can identify problem
   wells and prioritize their daily work process using the host software. Software packages such
   as Case Services' csBeamAnalysis also offer other functionality such as SPC (Statistical
   Process Control). SPC trending makes it possible to see how each value in a trend compares
   with the normal or average value of data points in the particular trend. SPC trending of
   runtime, production, card area, maximum/minimum load comparisons, and reports of
   pertinent data help the user make timely operational decisions. csBeamAnalysis allows the
   user complete and easy access for adding and changing wells, as well as data entry with a
   "point and click" interface.

Rod Pump Control Justification and Economic Benefits

   RPCs can help reduce operating costs and increase production by providing production
   operators and well analysts with information necessary for performance analysis, problem
   diagnosis and equipment optimization. Early pump off controllers (then called POCs) merely
   sensed “pump off” and were most effective with wells that could be over-pumped. Today’s

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Value of Rod Pump Control                                                   eProduction Solutions, Inc.

   RPCs can also be justified for wells that do not pump off because the tool enhances well
   surveillance and allows immediate identification of operating problems.

   RPCs improve profitability in many ways. When these controllers are integrated with a
   computer assisted operations (CAO) system, field-operating profitability can be enhanced
   even further.

      Operating Category          Benefits of Rod Pump                   Added Benefits with CAO

           Cash flow          Maximizes oil recovery by                Changes in inflow rate can be
                              matching system pumping time to          recognized in real time, allowing
                              well inflow capacity.                    corrective action to be initiated

                              Reduce unscheduled downtime              Operators can readily review and
                              because abnormal operating               adjust alarm/shut-down limits,
                              conditions (excessive fluid pound,       pump-off parameters, etc. to
                              high or low loads, etc.) can be          reduce failures. Failures can be
                              detected and the pumping unit can        easily recognized when they do
                              be shut down before severe               occur and corrective action can be
                              damage occurs.                           initiated immediately.

                              Reduced energy cost because              Operators can review and select
                              wells are not pumped when the            optimum idle times and pump-off
                              pump barrel is only partially filled     limits to maximize energy savings
                              with fluid.                              while assuring that production is
                                                                       not deferred.

        Reduced capital       Equipment can be run closer to           Predictive beam pump design
          investment          operating limits if it is continuously   programs can be modeled with
                              monitored and shut down when             observed operating conditions to
                              those limits are exceeded.               optimize equipment design and

                              Equipment will not require               Downhole pump cards can be run
                              premature replacement because of         by the operator and used to
                              damage caused by abnormal                optimize the setting of the pump-
                              operating conditions.                    off control parameters to minimize
                                                                       fluid pound.

    Improved surveillance     Operating parameters are                 In addition to alerting the operator
                              continuously monitored to detect         to anomalies in measured
                              anomalies in beam pumping                parameters at a central location,
                              performance.                             the system can monitor calculated
                                                                       parameters (e.g. rod stress, peak
                                                                       torque, pump efficiency, or unit
                                                                       out of balance).

                                                                       Operators can quickly focus
                                                                       attention on problem wells by
                                                                       using exception reports to screen
                                                                       analysis results and identify wells
                                                                       needing review and corrective

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Value of Rod Pump Control                                                    eProduction Solutions, Inc.

                                                                        Being aware of problems as soon
                                                                        as they occur will permit quicker
                                                                        prioritization and scheduling of
                                                                        needed corrective action.

     Improved production         Information monitored and stored       Accurate downtime is collected on
         accounting              by the wellhead controller can be      each well every day. In
                                 used to improve reporting of           conjunction with accurate well
                                 unscheduled downtime for               tests, this information can be used
                                 production allocation purposes.        to highlight deferred production
                                                                        and help prioritize corrective

     Improved safety and         Wells can be shut down if              Wells can be stopped and started
       environmental             monitoring devices that can be         remotely. This can be tied in with
         protection              installed indicate unsafe conditions   critical production facility alarms to
                                 (e.g. high flowline pressure,          shut down wells.
                                 stuffing box leakage, or tank

   RPCs with central site monitoring capabilities can improve the quality of well tests in locations
   that have automatic well testing by monitoring well performance during the well test.

   Operators often find themselves unable to obtain well test data as often or as accurately as
   they would prefer, especially in shallow well production fields. This issue most often results
   from the sheer number of wells drilled in a restricted geographical area and not enough test
   facilities to adequately handle them. In many cases, this type of production also depends on
   steam injection as a primary production technique. Because steam is primarily a gas, varying
   amounts of steam must be pumped back to the surface by the downhole pump, along with
   the oil and water given up by each well. The presence of steam further complicates the issue
   of unusable well tests. Many operators use the “inferred production” capability of RPCs and,
   in many cases, central site software in an effort to have reasonably accurate well test data as
   needed. Inferred production is the ability of an RPC to estimate accurate well pump
   displacement from every well everyday. This data from the RPC can be critical to information
   management, decision making and in some cases, it can be used in place of actual well tests.

   Economic Benefits

   Field-based experience with installed RPCs has allowed the documentation of the following
   average economic benefits:

                                           Stand-alone RPC                         RPC with CAO
          Energy savings             21%                                  22%

       Maintenance savings           28%                                  35%

        Net operating cost           $50-300 /well/yr.                    $300-800 /well/yr.
     Production acceleration         1%                                   2%

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Value of Rod Pump Control                                            eProduction Solutions, Inc.

   With this magnitude of savings, any field with beam pumping should be a candidate for
   effective microprocessor based RPCs and central site monitoring unless there is a very
   compelling reason not to do so.

   Economic Benefits Summary:

   Energy Savings: Energy savings result from reducing the operating or runtime of the
   pumping unit and still maintaining maximum production. The amount of power savings
   realized is a function of how the well was being pumped prior to RPC installation.

   Typically, wells are over-pumped to obtain maximum production but always at the cost of
   excess energy usage. The existing production methods may have been:

      •   A mechanical percent timer or pin-type timer.
      •   Twenty-four hour per day operation.
      •   Other operator-controlled on/off periods.

   Further, the ability to set the pumping unit shut down point at the first fluid pound stroke
   (when the pump barrel did not completely fill) and at an operator-selected consecutive
   number of fluid pound strokes, ensures that the well has indeed “pumped off” before it is
   shut down. The well is then able to obtain maximum pump fillage before the reservoir fluid
   flow into the wellbore is limited by increased wellbore pressure.

   “Fine-tuning” the RPC setup to specific well operating conditions so that the minimum
   pumping time and maximum idle time are obtained without any loss in production further
   enhances the amount of energy savings.

   Maintenance Savings: Two benefits in this area result from monitoring a well with an RPC:

      •   The RPC is designed to detect fluid pound when "pump-off" begins and can be set by
          the operator to limit the amount of fluid pound allowed. This prevents wear and
          damage to all components in the pumping system. It should extend equipment life by
          limiting the detrimental effects of fluid pound. By also reducing the number of pump
          cycles, the life of the pumping equipment will be extended.
      •   The RPC also monitors maximum and minimum rod loads, load span, and card area
          so that if a pumping system has a component failure (i.e., a stuck pump, a "sanded
          up" pump, a parted rod string, a tubing leak, standing or traveling valve leakage,
          etc.), the RPC will shut the unit down. This prevents further damage to pumping
          system equipment and may also provide power savings while the unit is not
          producing any fluid.

   Production Acceleration: Generally, any increase in a well’s production is a result of the
   RPC providing immediate significant operating information to the operator so that:

      •   Early detection and identification of potential pumping problems allow the operator to
          minimize down time due to downhole problems, and thereby prevent lost production.
      •   The RPC automatically increases the pumping cycle “run time” to compensate for a
          decrease in pump efficiency (slippage) or slight tubing leaks, thus maintaining
          optimum production. By monitoring the daily run time on a stable well, the operator
          can quickly be made aware of a potential well problem when the daily run time begins

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          to change over time. The operator can then schedule any needed well repair by
          monitoring the increase or decrease in daily run times.

   Manpower Utilization: Since an RPC can provide fault messages related to the problem it
   has encountered, operating personnel can easily determine corrective action as well as what
   type of equipment must be provided to effect needed repairs.

   If CAO is available, operating personnel no longer have to drive to each well before
   understanding whether the well is running or if it has an operational problem.

Causes of Lost Production
   •   A pump that is worn badly enough to prevent pumping all of the available production, but
       not badly enough to alert the producer of the need to have the pump pulled and
   •   A tubing leak that slowly grows larger and prevents the well from producing all available
       production until the leak is detected.
   •   A well that is “off production” for several days before the problem is discovered. Then,
       the well is often off for several more days before it can be repaired and returned to
       normal production.
   •   Improperly set pumping cycle idle times.

RPC Idle Time
   A key parameter in the set-up of any RPC is “how long to leave the pumping unit down”
   when pump off is detected – or “idle time”. Leave the unit down too long and production will
   be lost because of the increased backpressure placed on the producing formation by the
   rising fluid level in the casing from natural well inflow during the idle time. The amount of
   backpressure placed on the reservoir is a function of idle time duration. Leave the pumping
   unit down “not long enough” and the well will cycle (stop and start) too many times.

   The correct setting of the idle time value for an RPC is a primary key to the acceptance or
   rejection of well control. If the controller causes the operator to lose more revenue from
   decreased oil production than he is saving with reduced energy and well servicing costs, he
   will decide that an RPC is not a good application for his wells.

   For a well that is over-pumped and pumping 24 hours per day, the installation of a RPC will
   always result in some slight loss of production. The fluid that accumulates in the wellbore
   during idle time will cause some backpressure that will reduce the inflow into the wellbore.
   However, if the nature of the problem is understood, the lost production can be limited to a
   value that is economically prudent.

   The primary key to setting the idle time is the inflow performance of the well. This inflow
   performance is a function of the properties of the well. This inflow can be predicted by using
   the PI (Straight Line) or the IPR (Vogel Method). An accurate understanding of the well
   inflow performance is extremely valuable in getting the best performance from a well
   controlled with an RPC.

   •   Allows maximum production with reduced equipment failures.

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   •   Allows for quick and easy downhole problem detection.
   •   Increases system efficiency by pumping each well only as long as necessary to produce
       the available fluid.
   •   Increases rod, pump, and tubing life by eliminating fluid pound.
   •   Stores start-up, shutdown, and failure surface dynamometer cards for later analysis.
   •   Load-based shutdown limits can be set to avoid possible major pumping unit or downhole
       equipment failures.
   •   Correct RPC idle times can insure maximum production.
   •   RPC idle times that are too long can decrease production.

   Whether oilfield economics are good or bad, operators always look for new ways to improve
   production operations, reduce operating costs, and generally run a more cost effective
   operation. eProduction Solutions’ line of RPCs provide an excellent means of reducing power
   costs, maintaining or perhaps slightly increasing production, and reducing maintenance
   costs. The RPC microprocessor can be programmed to continuously monitor for pumping
   system malfunctions such as rod parts, load or position sensor failures, high or low load limit
   violations, or load span limit violations. If the operator-set operating limits are violated, the
   RPC can be programmed by the operator to take one of several basic actions:

       1. Turn on an alarm (fault) light only.
       2. Transfer well control to an internal “software timer” (software timer uses a calculated
          average run time from the last six pumping cycles).
       3. Transfer well control to the original pumping unit control panel (either "hand"
          operation or an external percent or pin type timer).
       4. Turn off the pumping unit until reset by an operator.

   Several basic examples of RPC-provided fault messages and possible corresponding
   problems are as follows:

   Control Failure
       •   HOA (Hand-Off-Automatic) switch left in hand operation or in the “off” position
       •   Motor panel control failure
       •   Pumping unit belt failure

   Low Load Span
       •   Parted rod string
       •   High fluid level
       •   Downhole pump valve failure
       •   Gas locked downhole pump

   Maximum Daily Runtime
       •   Tubing leak
       •   Downhole pump wear

   High Load
       •   Paraffin drag on the rod string or paraffin-caused high flowline pressure

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      •   Sand or trash sticking the pump plunger on the upstroke

   Low Load
      •   Stuck pump plunger on the downstroke
      •   Shallow rod part

   When wellsite RPCs are tied into a central monitoring and control (CAO) system, the above
   information is immediately available in the field office, or any other designated location on a
   local area network (LAN) or wide area network (WAN). Central site software shows alarms as
   they occur or they can be printed out as an alarm report, such as part of the morning report
   at the beginning of the workday. This allows only those wells with problems to be given

Summary of Reported Benefits
   Any number of technical papers are available that document the benefits obtained by RPCs.
   A summary of these papers is displayed in the table 2. This table highlights only the benefits
   reported. A complete reading of each paper is recommended if a full background of the
   operations involved is desired.

   Again, it should be noted that RPCs that are part of a central monitoring and control (CAO)
   system can offer the additional operating benefit of continuous diagnostic data that allows
   quick identification of problems so that corrective action can be taken before a problem
   becomes critical and unnecessary downtime is accumulated.

   The following are reviews of some recent RPC installations and the benefits obtained:

   East Texas Operator

   An operator in the East Linden (Cotton Valley) field in East Texas purchased and installed
   RPCs, replacing time clocks, on 15 wells. These wells are 10,000 feet deep, producing 42-460
   API gravity oil, with a 5 to 50% water cut. With contract pumpers and using timers set by
   trial-and-error, this operator saw the upside potential of using RPCs.

   Before installing RPCs, well problems were identified during daily visits. Timers were used to
   operate the wells – set based on a single visit to each well during a 24-hour period. The trial-
   and-error process used to set these timers would often result in some wells pounding fluid for
   long periods of time. Another problem was “under-pumping” some wells where pumping time
   was a little as 3 hr/day. Gas “break out” during this downtime resulted in the unrecognized
   need to pump the wells longer to move the gas as well as all available fluid. Factor in any
   pump wear – also requiring additional run time – and the possibility of “under-pumping” was
   very real.

   The installation of RPCs eliminated the guesswork and trail-and-error involved in setting time
   clocks for correct well control. The RPCs also automatically adjusted idle time based on
   buffered data in the controller from historical cycle times.

   Observed benefits from the use of RPCs by this operator include reducing rod and tubing
   failures by 31% and electrical cost by 40% ($50,000 per year). For wells that were
   maintaining a high fluid level due to incorrect timer cycles, the RPCs increased fluid

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   Town Site Lease

   An operator in Torrance, California operates a town site lease that has 41 air balanced
   pumping units (144" stroke) producing from approximately 3500 feet vertical depth (600
   measured depth). These highly deviated wells (400 average deviation with some wells over
   600) all have rod rotators to reduce rod and tubing wear. Prior to installation of RPCs, the
   wells were pumped 24-hours per day. The following is a general summary of costs prior to
   RPC installation and after.

     Cost Description             Before                     After            4 Mo. Prior to
     Direct well pulling    $51,899                $35,899                $48,201
       costs ($/Mo.)
      Electrical power      $46,476                $39,797                $41,050
       costs ($/Mo.)

   The average direct well pulling costs over the 28 months prior to RPC installation was
   $44,522 per month, therefore the $23,392 per month cost after RPC installation is a 47.5%
   savings. If compared to the more recent 16 months operation prior to installation (average
   monthly cost $50,990), it represents a 54.1% savings.

   Electrical power savings show the same significant results, but at the same time the
   controllers were put into operation the operator entered into an "interruptible power
   agreement" with the power company. This agreement resulted in a 22.8% discount in
   monthly power costs. This reduction must be subtracted from the total power savings in
   order to show RPC power savings.

   For the 28 months prior to installation of rod pump control, monthly power costs averaged
   $42,838 as compared to $23,897 per month after RPC installation or a 44.2% total power
   cost savings. Subtracting the interruptible power discount of 22.8% gives a 21.4% power
   cost savings due to the RPCs. If compared to the 16 months prior to the rod pump control
   installation, average power costs were $45,119 per month. The reduced power cost of
   $23,897 per month is a 47.0% total power cost savings, or 24.2% power cost savings due to
   rod pump control.

   Total daily production was maintained while making these significant reductions in well
   pulling costs and electrical power costs. The payback for the RPCs and central monitoring and
   control software was less than four months.

   Long Beach Installation

   Another operator in the Los Angeles area has seven wells on a town site lease in Long Beach,
   California. Four of the wells produce from 10,000 feet, and three from a shallower production
   zone. Daily average energy usage for the six months period prior to RPC installation was
   1964 KWH per day. A test was initiated by installing RPCs on two key wells. The daily
   average energy usage decreased to 1757 KWH per day over the four-month test period. This
   is an energy usage decrease of 10.5%. It was then decided to install RPCs on the five
   remaining wells. The daily average power usage decreased to 1488 KWH per day for a total
   energy usage decrease of 24.2%. Production has been maintained at the same level as prior
   to installation of RPCs.

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   An example of another of the benefits that can be obtained from information provided by an
   RPC occurred on one of the deep wells soon after the controller had been installed. In
   monitoring the cycle run time (length of pumping cycle in hours, minutes, and seconds) that
   had been quite constant, it was evident that the cycle run time was beginning to increase
   significantly. A well test was obtained and production was found to be below normal.
   Investigation showed that the tubing went on a vacuum, indicating a tubing leak or pump
   problem. The pump was pulled and inspection revealed that the pump seat had begun to
   wash out. It was decided to run a lead seal bottom plug to seal in what was estimated to be
   a slightly washed seating nipple. This solved the problem and prevented a tubing job that
   would have cost in excess of $10,000. This one early problem detection and resulting
   corrective action, provided by information easily obtained from the RPC, paid for four of the
   RPCs – simply by not having to do a complete tubing job. An additional benefit was the
   prevention of lost production.

   Test Results in West Texas

   An operator in West Texas recently installed 15 RPCs for a test evaluation. At the end of the
   test period, the operator reported an average 16% decrease in pumping unit run time (when
   compared to run time on timers), and an overall decrease of 25% in pulling costs, and a 5%
   increase in production.

   Far East Test Producing Lower Gravity Crude

   Initial results from a test conducted in the Far East using RPCs on rod pumped wells
   producing low gravity crude resulted in the following data:

        Description             Before RPC              After RPC                Benefit

      Operating time        240 Hours (33%)       180 Hours (25%)         25% decrease in run
      hours / month                                                       time

     Gross production       102.5 B/D             399.0 B/D               289% increase in

          Power             4843 KWH              3632 KWH                25% decrease in power
       consumption                                                        usage

         Power              47.25 KWH/BBL         9.10 KWH/BBL            80.7% decrease in
     consumption per                                                      power consumption per
        BBL fluid                                                         BBL fluid

   Operating cycles prior to RPC installation were handled manually with a typical run cycle
   being 24 hours “on” and 48 hours “off”. These operating cycles were partly due to the
   inaccessibility of the wells. With the RPC installed and an optimum idle time of 1-1/2 hours,
   the pump would then operate for 20 to 30 minutes before shutting down due to pump off.
   This more frequent production cycle with the RPC was much better suited to the well inflow
   characteristics of the well and therefore optimized production. This is an extreme comparison
   case, but clearly illustrates the tremendous advantages of RPCs on remote or difficult access
   (due to terrain or weather) wells.

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   Canadian Well

   An example of a serious problem avoided by RPC monitoring of a remote well in Canada
   occurred recently. The bolts on the Sampson Post bearing assembly loosened and before any
   damage was done the controller sensed abnormal loading and shut the well down. When
   routine well surveillance by the lease operator discovered the well down on a load fault,
   inspection of the pumping unit determined the cause. The problem was corrected and the
   unit was returned to normal operation.

Case Studies Summary
   These case studies again show that RPCs offer three basic benefits to the operator. These
   benefits are:

      •   Power Savings: An approximate 20% to 25% decrease in energy consumption is
          generally obtained.
      •   Maintenance Cost Reductions: An approximate 25% reduction is generally reported.
          This percentage depends heavily on the severity of the pumping conditions and the
          operator’s efforts to minimize failures prior to RPC installation.
      •   Production: Data from these studies supports a possible 4% increase in production.

   In addition to the three basic benefits mentioned above, RPCs should be considered
   especially applicable to:

      •   Wells in enhanced recovery programs that result in changing or cyclic well production.
      •   Inaccessible wells that do not receive adequate operator surveillance due to location,
          terrain, or weather.
      •   Wells with fiberglass rod strings to prevent compressive rod loading.
      •   Wells with severe pumping conditions such as high loads, high pumping speeds,
          corrosive downhole conditions, highly deviated wells, or other similar well and
          equipment conditions.

   The table 1 below gives a summary of the more recent operating experience covered in this

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   Case Studies Tabular Summary

         Operation                 Power              Maintenance/                Production and
                                  Savings           Operating Savings             Other Benefits

      East Texas Test       40% cost savings        31% well pulling cost       No data

        Torrance,           21.4 to 24.2% power     47.5 to 54.1% direct        No change
        California          cost savings            well pulling cost savings
      Townsite Lease

       Long Beach,          24.2% energy            Not established, but        No change
        California          usage decrease          saved $10,000 on one
      Townsite Lease                                early problem detection

     West Texas Test        10.6 decrease in        25% decrease in pulling     5% increase in
                            pumping unit run time   costs                       production

          Far East          25% decrease in power   No data                     289% increase - viscous
                            consumption                                         oil production sensitive
                                                                                to proper cyclic timing

                            Table 1: Economic and Operating Benefits

   Technical Papers Tabular Summary

        Techncal Paper                  Power             Maintenance/             Production and
           or Article                  Savings          Operating Savings          Other Benefits

    "Successful Application 10% to 35% reduction 10% to 35% reduction Up to 4% production
         Of Pump-Off                                                  acceleration
       Controllers" SPE
    Paper 6853 (1977) (1)

       "Denver Unit Well        15% decrease in        Not established            4% production
        Surveillance And        KWH/BBL                                           acceleration
       Pump-Off Control
      System" SPE Paper
        6849 (1977) (2)

     "Pump-Off Controller 48% decrease in              Not established            Did not increase
        Application For   power consumption                                       production, but
       Midway-Sunset                                                              provided a more
                                                                                  efficient method to
         Cyclic Steam
                                                                                  produce available
       Operations" SPE
    Paper 9915 (1981) (3)

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        "Shell Expands          20% to 25% decrease     Data indicated there      4% production
     Computer Production        In electrical power     should have been          increase
      Control" Oil & Gas                                substantial increase in
                                                        failures due to
      Journal (1981) (4)
                                                        increasing water cut.
                                                        This did not occur,
                                                        giving evidence that
                                                        system substantially
                                                        reduced maintenance

    "Pump-Off Controllers       25% average increase    96% decrease in           Production decrease
     Improve Sucker Rod         in the efficiency of    rod failures              was a field problem
      Economics" World          power consumed          83% decrease in pump      and not due to the
                                                        changes                   RPCs. Average pump
        Oii (1982) (5)
                                                                                  efficiency increased

       "Experience With         20% reduction in        25% reduction in          1% to 4% increase in
     Pump-Off Controllers       energy consumption      pulling expenses          production
    in The Permian Basin"
       SPE Paper 14385
          (1985) (6)

     "Computerized Auto- 11.3% decrease in              28.6 % decrease In        3.8% to 13.9%
       mation Of Oilfield  energy use per               subsurface failures per   increase in production
    Production Operations: barrel of fluid lifted       barrel of fluid lifted
    An Extensive Five Year
    Study into The Costs &
     Benefits" SPE Paper
      15392 (1986) (7)

      "Analysis Indicates       Although energy         14% decrease in lift      3% increase in
    Benefits of Supervisory     efficiencies can be     equipment failures        production
      Pump-Off Control"         expected to improve,
                                overall reduction
      Oil and Gas Journal
                                cannot be anticipated
       July 1, 1991 (8)
                                because of possible
                                in fluid production

                            Table 2: Economic and Operating Benefits

Putting It All Together – Why “Pilot” Test RPCs? - A Case
   Many lessons have been learned from practical application of RPCs over the past two decades
   concerning the best use of RPCs. Field testing obviously must be well thought out and there
   must be effective communication with lease operators and other key field personnel. The
   following discussion serves to re-enforce the results of other case histories discussed in this
   paper and can serve as a model for operators wishing to understand the implications of
   automation through the use of RPCs in their particular field situation.

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                     Lost Hills Field
                 San Joaquin Valley, CA
   With a large-scale waterflood project being implemented in this field, engineering efforts
   were focused on continuous well surveillance and timely waterflood response detection. An
   effective way to monitor waterflood response was to install RPCs on rod pumped wells. This
   method was especially effective since wells in this field could not be tested on a frequent
   basis. Because well tests might be obtained only once a month, the end result was the
   possibility that months could pass before waterflood response was measured. The installation
   of RPCs allowed percent runtimes to be monitored and used to identify flood response or well
   problems much sooner.

   The studies cited previously in this paper have shown the proven benefits of using RPCs – in
   addition to waterflood response detection. These benefits include reduced energy
   consumption, reduced well failure frequency, and increased production.

The Pilot
   With approximately 250 producing wells in the waterflood area, RPC installation on all pattern
   wells would be very expensive. The great capital investment would need to be economically
   justified. And, just as important, a pilot test would be a good way to develop field personnel
   acceptance. Concerns about automation and its implications were obstacles that had to be

   The field pilot was designed to:

      •   Prove that RPCs would or would not work in the Lost Hills field.
      •   Help lease operators develop support for the further use of RPCs.
      •   Be small enough to limit investment risk.
      •   Be small enough to be easily monitored.
      •   Provide enough data to enable a decision about the future use of RPCs.

   Nine closely spaced wells within a mile of the field office were selected for RPC installation.
   The pilot test was monitored for five months. It is important to note that these nine wells
   were monitored for two and one-half months before RPC installation and for two and one-half
   months after RPC installation.

   Again, three operating parameters were measured during the pilot:

      •   Electrical usage.
      •   Well failures.
      •   Production.

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Well Selection Criteria
   Waterflood Pattern Producers

   Rod pumped wells in a waterflood pattern benefit from the installation of RPCs even more
   than wells outside a waterflood area because of the quick detection of waterflood response.
   These well types are most suited for RPCs in a waterflood:

      •   Wells not yet showing waterflood response, but expected to in the near future.
      •   Wells with changing waterflood response.

   Wells Producing Sand

   Sand producing wells should be carefully identified and evaluated before installing RPCs.
   Sand settling in the rod-tubing annulus during the idle time of a normal RPC cycle may cause
   the pump plunger to become irreparably stuck.

   Wells with Gas Interference

   Wells with gas interference should also be identified when RPCs are installed. Severe gas
   interference can cause the surface dynamometer card to be erratic and perhaps result in
   premature well shutdown. Possible solutions to this problem:

      •   Configure the RPC to continue to pump the well when gas is present in the pump to
          minimize the possibility of premature well shutdown.
      •   Lower the pump below the bottom producing perforation.
      •   Install a gas anchor.

   High Failure Rate Wells

   Wells with high failure rates are generally the best candidates for RPCs because well failure
   reduction usually represents the largest savings associated with the benefits of RPCs. RPCs
   were preferentially installed on the wells with the highest historical failure rates.

   High Producing Wells

   High productivity wells are good candidates for RPCs. These wells generate the most revenue
   and it is important to react quickly to well problems and limit downtime. These wells operate
   more efficiently when RPCs are installed.

   Pumped Off Wells

   Wells located in a waterflood area should be over-displaced (pumped off) and therefore
   capable of handling waterflood response even before RPC installation. This also holds true for
   wells in areas of water encroachment or additional remedial potential. Several times during
   this pilot and field implementation, wells were found not be pumped off or to be under-
   displaced enough that they could not be pumped off. Time delays, additional expense, and
   inefficient use of manpower were the result.

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   Wells on Timer

   Wells operating on a pin type or percent timer are good candidates for RPCs. RPCs allow
   wells to automatically adjust to the dynamics of the reservoir. The well is pumped more
   efficiently and the RPCs adjust run time for pump wear – which a timer cannot do. Most of
   the increased production during the pilot test came from wells that had previously been on

   Energy Rebates

   Energy reduction rebates may be available from the local utility for RPC installation projects.
   Based on pilot results, energy rebates were typically the largest for those wells most over-

Well Equipment Selection
   Various methods for controlling rod pumped wells that experience pump off have been tried
   for many years. The most reliable method and the one that has gained the most acceptance
   has been the rod load versus position method. Polished rod loads can be measured in two
   ways, both of which are used in the Lost Hills field.

   One method is to weld a beam-mounted transducer (strain gauge) to the pumping unit
   walking beam. The second method is to install a polished rod load cell between the bridle
   carrier bar and the polished rod clamp. Both methods have pros and cons.

   The pros of a polished rod load cell:

      •   It is easier to install and remove from pumping units when compared to weld-on
          beam-mounted transducers.
      •   It does not need to be re-calibrated if the rod load changes, i.e., if the pump depth,
          pump size, or stroke length changes.
      •   It gives accurate and dynamic measurement of load.

   The cons of a polished rod load cell:

      •   It can be easily damaged by well servicing crews.
      •   It is subject to damage from certain abusive well conditions, especially floating rod

   The pros of a beam-mounted strain gauge:

      •   It requires less maintenance since it is not subject to conditions such as floating rod
      •   It is not in the way of well servicing crews because it is mounted on top of the
          walking beam.

   The cons of a beam-mounted (welded-on) strain gauge:

      •   It has exacting requirements for installation. Welding requires “hot work permits”,
          well cellars must be emptied, and any combustible materials removed from the

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           immediate area. Also, manufacturer’s specifications for installed location on the
           walking beam and welding temperature must be strictly followed.
       •   Removal from the walking beam is difficult.
       •   It must be re-calibrated each time there is a rod load change.

   The rod load versus position RPC has three methods of measuring the pumping unit polished
   rod position: an inclinometer, angle transducer, or a position/proximity switch. However, only
   the inclinometer is used at Lost Hills for the following reasons:

       •   When the strain gauge is used to measure rod load and an inclinometer is used to
           measure position, the two devices can be installed as a single unit.
       •   The inclinometer is always easier to mount than an angle transducer or position
           switch – requiring only a simple magnet to mount the inclinometer to the pumping
           unit walking beam.
       •   The proximity switch only measures position at one point during a single stroke of the
           pumping unit.

   Other factors considered were the supplier’s experience, stability, and quality of service.
   Costs and features of the equipment were also considered, as well as the potential for the
   equipment to be used as a part of a remote telemetry system.

Field Buy-in
   RPC projects will be much more successful if lease operators and other field operating
   personnel buy-in is obtained from the beginning. Skepticism about RPC usage was due to
   several reasons:

       •   Past experience with poorly designed controllers.
       •   The perception that RPCs would simply be “black boxes” on their wells.
       •   Concern that RPC implementation would result in manpower reduction.

   To gain support for RPCs, several steps were taken:

       •   Educating personnel about RPCs and the purpose of the project.
       •   Training courses in the operation of RPCs were held both in the office and in the field.
           From the beginning, the operators were made aware that their responsibilities would
           now include proper RPC operation.
       •   Operating personnel were involved in the well selection process – both during the
           pilot and field installation. This promoted teamwork, responsibility, and ownership.

   Obtaining field level support was the most critical step towards a successful RPC project. It
   should be noted that, to date, there has been no reduction in manpower. Rather, the role of
   a lease operator is simply changing from one of “problem-finder” to “problem-solver”.

   •   Involve lease operators and other key operating personnel from the beginning for a
       successful project.
   •   Lease operators/responsible personnel should be trained in the use RPCs.

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   •   Lease operators should approve of the installation of an RPC on each well.
   •   Selection criteria should be developed and utilized to identify the best candidate wells for
       RPC application.
   •   Both polished rod load cells and beam-mounted strain gauge work adequately to control
       beam pumped wells. Major consideration should be given to the use of polished rod load
       cells if well diagnostics is a requirement of the project.
   •   Inclinometers are the best position device.

   Since previous studies have proven the benefits of rod pumped control (RPCs), the Lost Hills
   field felt that a large, lengthy field trial was unnecessary. Instead, a small pilot was designed
   and implemented to show that RPCs would economically work at Lost Hills. During the pilot
   and field implementation, efforts were focused on the practical and efficient use pf RPCs,
   rather than on detailed data analysis.

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        Cost Justification Worksheet
   Use this worksheet to estimate the total yearly benefit available when RPCs are installed on
   beam pumped wells. Change the benefit percentages to be more conservative or more
   optimistic as the situation dictates.

   1.     Power Savings

          Current Energy Cost Per Year                      $

          21% Decrease in Energy Consumption                X          .21

          Power Savings                                                $

   2.     Maintenance/Operating Savings

          Direct Well Pulling Cost Per Year                 $

          28% Decrease in Pulling Cost                      X          .28

          Maintenance Savings                                          $

   3.     Production Increase

          Total Yearly Production                           $

          Price/BBL                                         $X

          2% Production Increase                            X          .02

          Production Increase                                          $

          TOTAL YEARLY BENEFIT (1+2+3)                                 $

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  Benefits of a Complete Rod Pump
           Control System
   The principles discussed in this paper have been implemented in fields with as few as 20 rod
   pumped wells to fields with more than 3,000 wells. Rod pump control systems have been
   installed in primary recovery fields as well as tertiary recovery fields undergoing water, CO2,
   or steam flooding. These systems have been installed in new fields with no automation in
   place and in mature fields that have been automated for over a decade.

   This discussion describes the financial benefits of implementing a comprehensive rod pump
   control system (well site RPCs and host diagnostic software) in the following different

      •   Increased production.
      •   Reduced operating costs and well failures.
      •   Individual well management.
      •   Efficiency in field operations.
      •   Efficiency in computer operations and automation.

   Increased Production

   Fine-Tuning Wells As Well Behavior Changes

   The analytical features of the diagnostic central-site software portion of a rod pump control
   system allow the user to make changes to the operational parameters of the wells at any
   time from the operating office. Changing the pump-off set point is an example of a
   parameter change that can be used to fine-tune production. By monitoring the performance

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   of the well on a daily basis, the operator can make small changes to the configuration of each
   wellsite RPC that can decrease the span of fluid level fluctuations.

   The rod pump control system (RPCs and host software) provides both surface dynamometer
   cards and calculated downhole pump cards for detailed analysis.

   In addition, using the various optimization tools, lower operating fluid levels are often
   achieved, which increases total fluid production. Assuming the same oil cut is applied to this
   increased fluid production, recovery of oil increases on a proportional basis.

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   Increased Runtime / Decreased Downtime

   The concept of managing wells by “exception” promotes the ability to keep downtime to a
   minimum in two ways. First, when a well does go down, the operator can be notified
   immediately – even if the operator is off the producing property. Second, these rod pump
   control system tools provide indications that a pumping well may be heading toward a failure
   of one type or another. In the second case, the user can prevent downtime rather than react
   to it by correcting the factors that are leading the well into a failure condition.

   Early Detection of Production-Robbing Problems

   Problems that reduce the production of a well can be seen through trends and displays of
   historical data as displayed by the host software used by the rod pump control system. By
   examining the calculated downhole card of a beam-pumped well, a user of the system can
   identify problems such as traveling valve and standing valve leaks, barrel / plunger fit,
   friction, unanchored tubing, and gas compression.

   Design Wells for Optimal Performance

   The host software also provides tools for designing and optimizing beam pump systems. By
   using “what-if” analysis, the user of the software can experiment with different parameters in
   a virtual environment before actually making changes in the field.

   From the combination of increased runtime along with rod pumping system optimization, this
   type of rod pump control system typically improves production in the range of 2% to 10%,
   depending on the current producing conditions.

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Reduced Operating Costs & Well Failures
   Reduced Electrical Costs by Optimizing Pumping Unit and Motors

   A comprehensive rod pump control system goes beyond a basic SCADA (Supervisory Control
   And Data Access) system’s ability to merely monitor and report on the data from rod
   pumped wells. Analytical tools are built into the host software so a user can perform a
   detailed analysis on the data gathered from the wellsite RPCs without moving the data into
   another diagnostic product.

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   For beam pumping installations, the user can evaluate different pumping units and prime
   movers, as well as over one hundred other parameters in a virtual “what-if” scenario. Rather
   than actually making the expensive changes at the well, the optimization software provides
   the user with a way to compare various parameter changes so the user can optimize each
   installation for pumping unit and motor size, rod design, or displacement matched to inflow.

   Additionally, the user has the ability to do “what if” analysis in designing or redesigning beam

   As previously stated, field experience and customer dialog has shown that the installation of
   a comprehensive rod pump control system (and optimizing electrical usage) will reduce total
   field electrical consumption in the range of 10% to 30%.

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   Reduced Manual Fluid Level Determination

   By taking advantage of the wave equation for downhole analysis, host software portion of the
   rod pump control system can provide an acceptable calculation of the fluid level of a beam-
   pumped well based on loads from the downhole card. The time and expense of regularly
   shooting fluid levels can be greatly reduced. Historical trends of calculated fluid levels are
   also available.

   Reduced Chemical Costs by Optimizing the Chemical Treatment Plan

   A comprehensive rod pump control system provides the user with card area trends. This
   trend is an excellent way to track any change in downhole conditions, including friction at the
   pump. If the trend is on an upward slant, it is an indication that friction is increasing.
   Experience with individual wells using this trend enables the operator to better schedule
   maintenance such as chemical treatments and pump changes.

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   The area of the surface card of each rod pumped well is displayed in a chart for easy

   Chemical Treatments Are Less Frequent but Effective

   By frequently analyzing the performance of the wells and incorporating historical information
   provided by host software, the user has accurate information that can help in more efficiently
   scheduling chemical treatments.

   Field experience and customer dialog has shown that the installation of a comprehensive rod
   pump control system (and optimizing chemical usage) will reduce total field chemical
   consumption in the range of 10% to 30%.

   Diagnose Problems without Pulling Rods or Tubing

   Through fine-tuning each RPC, the tools available in the rod pump control system allow the
   user to minimize rod stress and fluid pound. Another less tangible benefit is the ability to
   prioritize well work in the field to optimize rig usage and rig timing. The necessary
   information becomes immediately available from each beam pumped well to the operation
   office. Many problems and their causes are obvious based on the data received from each
   beam well. Examples include:

      •   Pump Wear
      •   Excess Friction
      •   Rod Overstress
      •   Gas Compression
      •   Gearbox Overload
      •   High Fluid Level Detection
      •   Tubing Anchor Slippage / Movement

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   Field experience and customer dialog has shown that the installation of a comprehensive rod
   pump control system (and correct diagnosis followed by the appropriate corrective actions)
   will typically reduce repair and maintenance expense by 10% to 30% per year.

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  Individual Well Management Well
     Management by Exception
   Rather than requiring an operator to examine each well’s status every day, the concept of
   management by exception is used to provide information about anomalies through alarm and
   color-coded grids. The rod pump control system alerts the user to any parameter that is out
   of an ordinary operating range as defined by the user. This allows the user to focus on
   prioritizing recognized problems, rather than searching for problems that may or may not

   Early Detection of Well Performance Degradation

   By monitoring the daily runtimes of each beam pumped well in a field, the first indication of a
   change in the operating conditions of the well visually prompts the user for proactive
   corrective measures. Further inspection may show an increase in the area or size of the
   card, excessive gearbox torque, and a reduction in the rate of fluid pumped, etc. The
   information presented from each of those indicators provides the user with a strong start in
   recognizing problems at an early stage and taking appropriate measures to fix them.

   Comparison of Well Test to Theoretical Limits and Target Values

   Users of a rod pump control system have the ability to use information from different parts of
   the production operation to evaluate the state of the beam pumped wells and related
   production facilities. The well test information can be compared to the calculated fluid
   production of each well, and this total from the wells (feeding a particular facility) can be
   compared to the actual metered sales from that facility.

   Notification of Wells Operating Out of Parameters Based on Artificial
   Lift Analysis

   Beyond exception notification from RPC parameters, the rod pump control system provides
   notification and alarms based on the analytical calculations performed within the host
   software portion of the rod pump control system.

   Early Detection of Changing Wells Due To Automation

   Alarms can be programmed to alert users that a beam well has begun to run too long or not
   long enough. The user can even be alerted after hours through call-out programs that can
   page or call with information about the alarm.

   Routine Management and Reporting

   The rod pump control system provides historical reports and graphs that represent normal
   operating conditions for each rod pumped well. Since this data is a part of an overall
   database, it can be used for calculating accurate production data. The installation of a
   comprehensive rod pump control system (and operating by exception) will redirect
   manpower to better focus on corrective and optimization measures. This prioritizing of

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   operations staff time and redirection of the existing personnel to work on immediate needs is
   effectively equal to hiring additional staff.

   Typically, effective manpower improves beyond the pre-optimization application to a point
   where this (effective manpower) can offset new expenses to maintain wellsite RPC

Efficiency in Field Operations
   Reduced Windshield Time

   Data from each rod pumped well is displayed by the host software in the production office
   and is presented in a way that facilitates understanding the condition of a large number of
   wells. Companies that use a complete rod pump control system have found that they can
   substantially reduce the time necessary for someone to visit and personally inspect each
   well. Wells still need to be visited, but site visit frequency can be reduced substantially,
   which frees personnel for priority problem solving or other proactive activities. From past
   experience, site visits to each well have been reduced from daily to weekly or monthly,
   depending upon the operating philosophy of individual companies.

   Two examples of cost reduction in “reduced windshield time” include: 1) more effective
   dynamometer collection and 2) more effective fluid level collection.

   More Effective Dynamometer Collection

   Assume that a well analyst can make 400 “on site” dyno runs per year, or an average of
   about eight surveys per week. Assume the total cost of dynamometer collection for one year
   is $48,000 or $120 per dyno survey. Further, assume that the same well analyst can
   analyze 100 wells using dynamometer surveys gathered by the optimization software in one
   week. At 12 times faster collection pace per year or 4,800 dyno surveys, and using the
   same $48,000 annual survey cost, this would equate to a per dyno cost of $10 ($48,000 /
   4,800). Instead of analyzing 400 wells in a year’s time, simple math dictates that 4,800
   dyno surveys can be taken using the rod pump control system during the same one-year

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   The graph depicts this example as a one-year phase-in redistribution of a well analysts’ time.
   The real advantage of this example is time redistribution, which could then take the form of
   1) more analytical time for optimizing lift equipment, 2) proactive maintenance of RPCs, and
   3) attention to those remote or “low impact” wells, not previously covered by operating

   Often, just the collection of well data on so-called “low impact” wells will reveal inappropriate
   operating practices, which can present upside opportunities, dramatically reversing the
   prevailing perception of remote wells or fields.

   More Effective Fluid Level Collection

   Assume that a well analyst or lease operator can shoot 10 fluid levels per day and the cost is
   $17.50/hour. Over one year, the total fluid levels collected would cost approximately
   $33,600 or about $14 per fluid level collected. Assume that 100 calculated fluid levels per
   week are collected by using calculated fluid levels gathered by the rod pump control system
   host software. Over a one-week period, twice as many fluid levels are collected. Therefore,
   the fluid level collection cost would drop to about $7 each.

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   Assuming the same one-year phase-in as before, the graph depicts the relative savings or
   time redistribution. This redistribution of time could be better utilized for optimization of lift

Alarm Notification and Management
   Reduce or Eliminate Answering Services

   The rod pump control system host software is integrated with current state-of-the-art call-
   out systems. These call-out systems take over the role provided by the answering services.
   An answering service typically only helps in calling people when problems are detected by
   automation systems. Rod pump control systems not only provide problem detection, but
   also provide more specific information regarding the cause of the problem, enabling field
   personnel to make improved decisions in case of emergencies. Using the rod pump control
   system, personnel can also take corrective action from their homes.

   Reduce or Eliminate 24 Hour Duty

   An operator can be paged or called after hours because of an alarm and be given information
   about the problem. More than that, the operator does not need to leave his home to get
   detailed information about what is happening at the field. He can use the rod pump control
   system to connect to the field system remotely and see this information.

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Comprehensive Power Management System to Reduce
Electrical Costs
   For almost all oil fields, electrical costs account for a substantial percentage of the operating
   costs. Because of the flexibility in configuration and various optimization tools, operating
   companies have used the following solutions to help reduce their electrical costs:

      •   By using the information provided by the rod pump control system, scheduled
          shutdown of intermittent pumping wells during peak power demand can optimize
          power consumption, saving considerable expense.      Customized startup of rod
          pumped wells can aid in controlling spikes in power consumption after a power
          shutdown has occurred. In essence, this becomes a reverse peak shaving scheme to
          reduce power consumption during general peak usage.
      •   The host software can be used to ensure power utilization at any given time does not
          cross a certain threshold, thereby benefiting both the operating company and the
          power company.

Advanced Field Control Reduces Fluid Spills and Loss
   Because the rod pump control system is a part of an integrated field system, field wide
   control is available that is usually not present with typical SCADA systems. For example, it
   includes several standard control features for a rod pumped field, such as shutting down
   wells when tank levels are exceeded.

   Because of this advanced capability, the operator has a higher level of confidence in
   detecting leaks or high tank levels and thus avoiding the costs associated with clean up of oil
   or salt water spillage. The operating company also spends less time addressing issues with
   landowners, land men, lawyers, and negotiators.

Daily Production Reporting
   A comprehensive daily production report is provided from the rod pump control system. This
   report displays estimated production based on the downtime and the last known good well
   test of each well, shrinkage analysis by comparing the tested production to sales meter
   readings, and estimated lost production due to downtime of rod pumped wells.

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Value of Rod Pump Control                                            eProduction Solutions, Inc.

   Current information about daily, weekly, and monthly field and well production can be
   displayed. The production summary report can be obtained daily for different areas of the
   field or the whole field. Based upon the information presented in the production summary
   report, field management and personnel can better optimize their resources and prioritize
   which areas need attention.

Proactive Maintenance versus Reactive Maintenance
   Since the rod pump control system helps identify problems before they actually occur, field
   personnel can be proactive when scheduling field maintenance work. For example:

      •   Tubing anchors that are not holding, do not have enough tension, or that are slipping
          can be identified and tagged for immediate correction. Such proactive maintenance
          will prevent actual production losses, rod and tubing “friction” failures, and possible
          casing leaks.
      •   Daily examination of data for gearbox overloads or rod string overstress can prevent
          expensive failures through proactive correction and/or optimization.

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Value of Rod Pump Control                                             eProduction Solutions, Inc.

   Implementation of a comprehensive rod pump control system will impact the entire
   operation of a rod pumped oil field. The following diagram shows the relationship between
   technology, skills, and organization:

   The benefits described are always a result of the combination of changes in production
   operations in all three of these areas. It may involve changes in job roles and responsibility
   for field personnel. Note that the “foundation” of the triangle is the Organization.

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Value of Rod Pump Control                                                 eProduction Solutions, Inc.

  The eProduction Solutions Line of
   Rod Pump Controller Solutions
   eProduction Solutions is the industry leader in providing RPCs with tens of thousands
   installed and operating worldwide. eP’s RPCs operate a sucker rod pumping system in the
   most efficient way while monitoring the system for any possible problem.

CAC 8800 Rod Pump
   The CAC 8800 RPC is easy to
   use     by   field   operating
   personnel. The local wellsite
   display    provides     readily
   understood messages related
   to pumping system conditions.
   The keyboard allows users
   access to dedicated keys for
   important    functions,    e.g.
   “CLEAR ERRORS”, etc. No
   computer codes, special skills,
   or additional equipment is

   The firmware is backward compatible with all previous CAC RPC models
   (8500/8650/8700) and central host software systems – providing turnkey solutions for
   every beam pumping field.

   Designed for Reliable Operations
      •   Conformally coated boards provide extra protection from operating conditions such as
          sour gas
      •   Wide voltage input operating range protects the RPC against field power spikes and
          “brown out” situations
      •    Protection from lightning and other transient voltage events

   Easy to Use
      •   Easily understood messages and simple to use keypad. No additional equipment
          needed for RPC configuration or parameter display.
      •   Automatic setup for many well applications.
      •   Operator selectable set points and action for each fault condition.
      •   Built-in traveling valve and standing valve check capability.
      •   Parameters and data protection from power loss.

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   Modular Design for Upgrades
      •   Multiple operator interface options.
      •   Multiple auxiliary I/O options.
      •   Field communications and I/O options.
      •   An optional dual channel RS-232-485 serial expansion card for scanning other field

   Standard Features
      •   Recognition of changing well inflow characteristics “on the fly” to maximize production
          and minimize runtime.
      •   Multiple control methods available for differing pumping conditions.
      •   Configurable load based alarms – high load, low load, low load span, and low average
          load. Low average load can be used in heavy oil situations where “rod float” causes
          low load alarm problems.
      •   Algorithm to handle “inoperative pump problems” caused by trashy fluids or viscous
      •   Pump up delay timer – eliminates immediate pump off caused by incomplete pump
          fillage following well idle time.
      •   Cycle and run-time buffers for easy access to historical data.
      •   Card buffers – access to event cards and several cards leading up to the event .

   Unique Features
      •   Air Balance Control option automatically balances air balance pumping units.
      •   CDPD compatible.
      •   Peak Energy Control option can stop pumping operation during periods of peak
          energy demand/cost.
      •   Motor Restart Protection prevents motor failure when moisture condensation is
          present on motor windings.
      •   Controls virtually any pumping unit configuration, including improved geometry units,
          long stroke units, and two-stage pumps.
      •   Power fail recovery feature automatically pumps wells down when power is restored.
      •   Programmable I/O for unique monitoring (flowline pressure, casing pressure, stuffing
          box leak detector, etc.) and control applications.
      •   Inferred production determination for shallow wells allows measurement of total fluid
          production from each well. This data is stored for every pumping unit stroke, daily,
          and historically for 29 days.
      •   Automatic idle time adjustment feature allows the RPC to change the off-time
          between cycles as well conditions change.
      •   Control of two pumping systems operating in a single wellbore with one RPC.
      •   Stable operation in temperatures from –40oF to +185Fo (-40oC to +80oC).

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Value of Rod Pump Control                                             eProduction Solutions, Inc.

Model 2000 Rod Pump Controller
   This controller has all the features and functionality of the CAC 8800 RPC. This controller is
   meant to be a lower cost alternative to the 8800 RPC based on enclosure, user interface,
   and other optional features.

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Value of Rod Pump Control                                            eProduction Solutions, Inc.

ePIC Rod Pump Controller
   This controller was developed with all the features of the CAC 8800 and the Model 2000
   RPCs plus a number of new functions as a part of eProduction Solutions mission to provide
   the best decision making opportunities for operators of rod pumped oilfields.

   Exceptional Intelligence and Wellsite Control

   Expanded and enhanced technology found in the ePIC RPC:

      •   Wellsite   alarms      and
          system diagnostics
      •   Selected pumping system
          alarms based on host
          software analysis of well
      •   Card area alarms for the
          detection of deep rod
          parts      and     downhole
          friction identification
      •   Wellsite valve checks and
          CBE          determination
          available to host analysis
      •   Improved data      storage
          and trending
      •   Enhanced     data-logging
          function that allows any
          RPC register to be logged
          and used in application
      •   Programmable Intelligent Control Language (PICL) that provides the operator with
          flexibility to modify control logic to adapt to specific well conditions
      •   Inferred production for deep wells based on host software calculation of downhole
          pump stroke – without complex wellsite configuration
      •   Monitor only mode – provides surface dynamometer cards without regard to control
          setpoints or SPM range, ideal for monitoring pumping wells under Variable Speed
          Drive control
      •   Expanded alarms – host based alarms: gearbox torque, rod stress, pump efficiency,
          prime mover size, unit unbalance, load cell drift
      •   Hi-Hi, Hi, Low-Low, Low load alarms
      •   Simplified wellsite RPC configuration, data management, system diagnostics, and
          load cell calibration. Improved menu-driven interface for viewing dynamometer cards,
          viewing runtime information, and obtaining and storing valve check/CBE data
      •   Simple, three-step load cell or strain gauge calibration

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Value of Rod Pump Control                                               eProduction Solutions, Inc.

iBEAM Rod Pump Controller (Patent Pending)
   The addition of the iBEAM RPC adds a low-cost solution to eP’s family of rod pump solutions.
   This controller is meant to allow the benefits of eP’s RPCs to be applied to wells whose
   production has, in the past, not been sufficient enough to justify automated control. iBEAM
   features a simple cable-less installation, load and position technology, integrated host
   communications, wireless control, and low maintenance all in a completely self-contained,
   low cost unit. The iBEAM can be easily installed by attaching a built-in clamp to the pumping
   unit walking beam and connecting the communication module to the well-control panel. The
   iBEAM requires no cables, therefore there are
   no ditches to dig and more importantly, there
   are no cables to wear out. The RPC contains
   host communications, solar power supply,
   load and position sensors, and integrated
   intelligence to remotely operate rod pumped

   Many operators are reluctant to install RPCs
   on their low producing wells because of the
   capital, installation, and maintenance costs
   involved. Because of its wireless design, the
   controller is able to eliminate maintenance
   costs associated with cables to the load cell
   and position sensor. Additionally, the
   controller’s compact design provides savings
   resulting in a low-priced controller with high-
   tech capabilities. The advanced radio
   technology that is imbedded is used to control
   the well and relays operational data to a host-
   based software system for remote monitoring
   and detailed analysis. The radio also provides
   data to a hand held device for operators to
   use while visiting the wellsite.

   The controller uses advanced strain gauge technology for load measurement and
   accelerometer technology for measuring polished rod position together as the most effective
   way to control rod pumped wells. The controller creates a dynamometer card that is used to
   identify pump-off conditions and other potential problems that can occur in a rod pumped

   Filling the Need:
                          Needs                                             iBEAM
    Eliminate end device cables                      No end device cables
    Integrated SCADA communication                   Integrated SCADA radio included
    Proven technology to optimize wells              Load and position based technology
    Cost effective solution                          Solution cost under $2000
    Reliability                                      Technology currently used on 25,000 wells
    Easy installation                                Completely self-contained

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ePAC Rod Pumping System
   The ePAC rod pump control system goes beyond conventional variable frequency or speed
   drives. This solution incorporates Vector Flux Drive (VFD) technology for precision control of
   both speed and torque for optimizing rod pumped artificial lift systems. The ePAC has a
   proven track record of performance
   enhancements with conventional pumping
   units and long-stroke units such as the

      •   Infinite speed control
      •   Independent up/down stroke speeds
      •   Reduces power consumption
      •   Eliminates excessive rod loads
      •   Provides an optional methodology
          that eliminates bridle separation
          from the polished rod
      •   Uses pump fillage        algorithms to
          optimize production
      •   Maximum torque available from “0”
          to base SPM

   Many conditions using conventional pumping
   units are particularly suited to slow SPMs.
   Heavy oil applications requiring steam
   injection, wells that produce sand, low reservoir pressure conditions, and high water cut wells
   are prime candidates for the ePAC solution. Where conventional speed controls have yielded
   inefficient results, the ePAC overcomes the problems of traditional control with variable
   speed and torque control.

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Works Cited in this Paper
   •   Acton, Jeff F., "Pump-off Controller Application for Midway-Sunset Cyclic System
       Operations", Paper SPE 9915 presented at the 1981 California Regional Meeting,
       Bakersfield, CA. (March 25-26, 1981).
   •   Amezcua, Joe D., "Pump-off Controllers Improve Sucker Rod Lift Economics", World Oil,
       Feb. 1, 1982.
   •   Blackford, Todd A., Dunn, John R., Joseck, Randy R., "Analysis Indicates Benefits of
       Supervisory Pump-off Control", Oil and Gas Journal, July 1, 1991.
   •   Eckel, Andy, Abels, Harold, and Merritt, Ross: “Testing and Practically Applying Pump-Off
       Controllers In a Waterflood”, Paper SPE 29636 presented at the 1995 Western Regional
       Meeting in Bakersfield, CA. (March 8-10, 1995).
   •   Hunter, J. D., Hubbell, R.S., Reiter, C.R.: "Denver Unit Well Surveillance and Pump-off
       Control System", Paper SPE 6849 presented at the 1977 SPE Annual Technical
       Conference and Exhibition, Denver, CO. (October 9-12, 1977).
   •   Jentsch, Jr., W. A., Marrs, R. D., "Computerized Automation of Oilfield Production
       Operations: An Extensive Five Year Study into Costs and Benefits", Paper SPE 15392
       presented at the 1st Annual Technical Conference and Exhibition, New Orleans, LA.
       (October 5-8, 1986).
   •   Neeley, A. B., "Shell Expands Computer Production Control", Oil and Gas Journal.
       (March 23, 1981).
   •   Neeley, A. B., Tolbert, H. O., "Experience with Pump-off Control in the Permian Basin",
       Paper SPE 14345 presented at the 60th Annual Technical Conference and Exhibition,
       Las Vegas, NV. (Sept. 22-25, 1985).
   •   Ray, L.I.: Using Downhole Displacement and Inferred Production for Verification of
       Measured Test Data”, Paper SPE 62540 presented at the SPE/AAPG Western Regional,
       Long Beach, CA. (June 2000).
   •   Westerman, G. Wayne: "Successful Application of Pump-off Controllers", Paper SPE 6853
       presented at the 52nd Fall Meeting, Denver, CO. (October 1977).
   •   C. Nelson: “Benefits of Rod Pump Control”, CAC, Kingwood, TX.

   As the leading provider of oil and gas production automation systems, eProduction
   Solutions, based in Houston, Texas, pioneered the market for single-source automation
   software for producing oil and gas fields. This software is used by major oil and gas
   companies to run over 15,000 wells around the world.

              eProduction Solutions, Inc.
              22001 North Park Dr.
              Kingwood, TX 77339

              Phone:         281-348-1000
              Fax:           281-348-1280
              Web Site:

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